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From: Greg <itooo-xVucS5mfmt0AvxtiuMwx3w@public.gmane.org>
To: Gandalf Corvotempesta
	<gandalf.corvotempesta-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Cc: "ceph-devel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org"
	<ceph-devel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
	ceph-users-Qp0mS5GaXlQ@public.gmane.org
Subject: Re: RBD vs RADOS benchmark performance
Date: Mon, 13 May 2013 17:10:37 +0200	[thread overview]
Message-ID: <5191026D.4030004@itooo.com> (raw)
In-Reply-To: <CAJH6TXhcgNOLE53eJoJamwE3i-FSfBf9LzpRACHwp_hEriH5zA-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>

Le 13/05/2013 17:01, Gandalf Corvotempesta a écrit :
> 2013/5/13 Greg <itooo-xVucS5mfmt0AvxtiuMwx3w@public.gmane.org>:
>> thanks a lot for pointing this out, it indeed makes a *huge* difference !
>>> # dd if=/mnt/t/1 of=/dev/zero bs=4M count=100
>>>
>>> 100+0 records in
>>> 100+0 records out
>>> 419430400 bytes (419 MB) copied, 5.12768 s, 81.8 MB/s
>> (caches dropped before each test of course)
> What if you set 1024 or greater value ?
> Is bandwidth relative to the read ahead size?
Setting the value too high degrades performance, especially random IO 
performance.
You have to determine  the right choice for your usage.

Cheers,

      parent reply	other threads:[~2013-05-13 15:10 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <518D2B76.9040706@itooo.com>
     [not found] ` <1368423516.6771.2.camel@localhost>
2013-05-13 12:26   ` RBD vs RADOS benchmark performance Greg
2013-05-13 13:55     ` [ceph-users] " Mark Nelson
2013-05-13 14:52       ` Greg
     [not found]         ` <5190FE49.1030307-xVucS5mfmt0AvxtiuMwx3w@public.gmane.org>
2013-05-13 15:17           ` Mark Nelson
     [not found]     ` <5190DBD9.9070500-xVucS5mfmt0AvxtiuMwx3w@public.gmane.org>
2013-05-13 15:01       ` Gandalf Corvotempesta
     [not found]         ` <CAJH6TXhcgNOLE53eJoJamwE3i-FSfBf9LzpRACHwp_hEriH5zA-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2013-05-13 15:10           ` Greg [this message]

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